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About

About

I have been working at INESCTEC since 2014, where I am integrated in CAP | Center for Applied Photonics.

As a Chemist, I have extensive background and experience in synthesis, characterization and (on a long list of) various laboratorial techniques, including the determination of photophysical properties. My experience began in a more biochemical-focused area with health-related studies, with animal supplementation applications for produce improvement, and later with methods for valorization of primary industry by-products.

Within the 7th FP of the EU (SNIFFER), I helped develop an intelligent network capable of detecting threats both in the food supply chain and in the prevention of (bio)terrorism. Sensors have been developed as well as ionic liquids with different properties, capable of being used as "bridges" to other sensors or sensitive structures, or to act as sensors themselves. Within the scope of CORAL, I developed sensors for the detection of chemical species in aqueous medium (NO3-, NO2- and PO4-), with the purpose of creating conditions for social and economic sustainability in marine exploitation. At this time, I'm a part of AGRINUPES project which aims to create sustainability conditions in agriuultural exploitations, namely through water and nutrient sustained usage; in order to attain this I research and develop sensors capable of determining their concentration "in situ", assuring their adequate fertilization, promoting ecological and finantial economy.

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Details

Details

001
Publications

2018

Quantification of Ethanol Concentration in Gasoline Using Cuprous Oxide Coated Long Period Fiber Gratings

Authors
Monteiro Silva, F; Santos, JL; Marques Martins de Almeida, JMMM; Coelho, L;

Publication
IEEE Sensors Journal

Abstract

2016

Antimicrobial effect of essential oils of Laurus nobilis L. and Rosmarinus officinallis L. on shelf-life of minced "Maronesa" beef stored under different packaging conditions

Authors
Vilela, J; Martins, D; Monteiro Silva, F; Gonzalez Aguilar, G; de Almeida, JMMM; Saraiva, C;

Publication
FOOD PACKAGING AND SHELF LIFE

Abstract
The aim of this study was to evaluate the effect of essential oils (EOs) of plants naturally occurring in northern Portugal on the spoilage of fresh Maronesa beef burgers stored at 2 and 8 degrees C under different packaging conditions. EOs were obtained from dried leaves of laurel (Laurus Nobilis L.) and rosemary (Rosmarinus officinallis L.) by hydro-distillation using a Clevenger-type apparatus. Analysis of volatile composition of essential oils of rosemary and laurel was achieved by Gas Chromatography-Mass Spectrometry (GC-MS) and Gas Chromatography-Thermal Conductivity Detection (GC-TCD) resulting in the detection of 95.8% and 89.4% of its compounds, respectively. Fresh beef (semitendinosus and semimembranosus) of DOP-Maronesa breed (males; n = 4) were obtained from local market and transported to the laboratory. Samples were stored at 2 and 8 degrees C in two different conditions: aerobiosis (A) and vacuum (V) and analyzed at 0,1, 2, 3, 5, 7,10,14, 21 and 28 days for Lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonas spp., Fungi, Total mesophilic (TM) and psychrotrophic (TP), color (L*a*b*) and pH. Laurel was the most effective EO keeping pH from increasing. Coordinates L* and a* were higher on samples containing laurel EO for both A and V packaging. Laurel also showed better effect in reducing microbiologic counts in samples packed in A at both 2 and 8 degrees C and packed in V at 8 degrees C. Rosemary was effective in reducing microbial counts on all V samples stored at 2 degrees C. This study allows to conclude that Laurel EO has significant effect in shelf-life, maintaining fresh beef color.

2016

Involvement of endothelium in the vasorelaxant effects of 3,4-DHPEA-EA and 3,4-DHPEA-EDA, two major functional bioactives in olive oil

Authors
Segade, M; Bermejo, R; Silva, A; Paiva Martins, F; Gil Longo, J; Campos Toimil, M;

Publication
JOURNAL OF FUNCTIONAL FOODS

Abstract
The olive oil polyphenols 3,4-DHPEA-EA and 3,4-DHPEA-EDA displayed an endothelium dependent vasorelaxant effect in rat aorta, starting at similar to 1 mu M and abolished by N-G-nitro-L-arginine (L-NA) or N-acetylcysteine, and an endothelium-independent vasorelaxant effect, starting at similar to 10 mu M. Hydroxytyrosol only presented an endothelium-independent effect at 100 mu M. DHPEA-EA and 3,4-DHPEA-EDA, but not hydroxytyrosol, also increased NO generation within endothelial cells. At higher concentrations, the three compounds reduced argininevasopressin-induced increase of cytosolic Ca2+ concentration ([Ca2+](c)) in vascular myocytes. By UV-visible spectroscopy, we found that these polyphenols undergo autoxidative processes in organ-bath conditions. Thus, 3,4-DHPEA-EA and 3,4-DHPEA-EDA have an endothelium-dependent vasorelaxant effect caused by an enhanced NO production, probably through a redox mechanism within endothelial cells and an endothelium-independent vasorelaxant effect mediated by a reduction of agonist-induced [Ca2+](c) increase in vascular myocytes. Bearing in mind the plasmatic concentrations of these polyphenols following dietary intake of olive oil, these effects could modulate vascular tone in vivo.

2014

Effects of the dietary incorporation of olive leaves on growth performance, digestibility, blood parameters and meat quality of growing pigs

Authors
Paiva Martins, F; Ribeirinha, T; Silva, A; Goncalves, R; Pinheiro, V; Mourao, JL; Outor Monteiro, D;

Publication
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

Abstract
BACKGROUND: In a preliminary study the oxidative stability and tocopherol content of pork meat were shown to be improved by olive leaf (OL) feed supplementation at 50 and 100 g kg(-1). However, growth performance was affected negatively. Therefore the objective of the present study was to assess the influence of OL supplementation at a lower level on feed digestibility, growth performance and meat quality. RESULTS: Pigs were fed a basal diet (control), a basal diet with 25 g OL kg(-1) (OL2.5) or a basal diet with 50 g OL kg(-1) (OL5). The incorporation of OL significantly decreased growth rates (P = 0.010) and backfat thickness (P = 0.035) and increased feed/gain ratio (P = 0.032) in the OL5 group. Feed/gain ratio increased more for females (P = 0.001). The incorporation of OL decreased the crude fat (P = 0.006) and protein (P = 0.037) digestibility of both OL diets. Nevertheless, OL was effective in increasing the tocopherol content of meat (P = 0.009). However, meat from pigs fed the OL diets showed similar conjugated diene content, pH and colour parameters to that from pigs fed the control diet, even after 6 days of storage at 4 degrees C. CONCLUSION: The data indicate that olive leaves may be included in pig diets at 25 g kg(-1) in order to improve the tocopherol content of meat without excessively compromising growth performance. (C) 2014 Society of Chemical Industry

2013

Protective Activity of Hydroxytyrosol Metabolites on Erythrocyte Oxidative-Induced Hemolysis

Authors
Paiva Martins, F; Silva, A; Almeida, V; Carvalheira, M; Serra, C; Rodrigues Borges, JE; Fernandes, J; Belo, L; Santos Silva, A;

Publication
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY

Abstract
The capacity of important hydroxytyrosol metabolites (homovanillyl alcohol, hydroxytyrosol acetate, homovanillyl alcohol acetate, hydroxytyrosol 3' and 4'-O-glucuronides, and homovanillyl alcohol 4'-O-glucuronide) to protect red blood cells (RBCs) from oxidative injury induced by the radical initiator 2,2'-azo-bis(2-amidinopropane) dihydrochloride (AAPH) or by the natural radical initiator H2O2 was evaluated. In the presence of AAPH, all compounds showed to protect RBCs from hemolysis in a dose-dependent manner, exccept for the homovanillyl alcohol glucuronide, with the order of activity being at 20 mu M hydroxytyrosol > hydroxytyrosol glucuronides = hydroxytyrosol acetate = homovanillyl alcohol = homovanillyl acetate > homovanillyl alcohol glucuronide. At 10 mu M, hydroxytyrosol, hydroxytyrosol acetate, and hydroxytyrosol glucuronides still protected hemoglobine from oxidation and from morphological RBC changes. In the presence of H2O2, hydroxytyrosol showed to significantly protect RBCs from oxidative hemolysis in a dose-dependent manner, but the hydroxytyrosol glucuronides showed only a limited protection that was independent of the concentration used.